In the production of various textiles, a mat of filaments or fibers is subjected to so-called needle jets of water at extremely high pressure so as to entangle the filaments and impart a desired bulkiness to the mat. This is done by passing the mat underneath a nozzle beam that extends horizontally above the moving mat or web and that emits one or more rows of the needle jets, the row or rows extending perpendicular to the web/mat travel direction.
The nozzle beam as described in U.S. Pat. Nos. 4,069,563, 5,692,278, and 6,012,654 has an elongated housing formed with a downwardly open chamber that is pressurized with the treatment liquid, typically water, and that extends as mentioned above transversely to the web/mat travel direction. The bottom wall of the housing is formed with an elongated slot and is formed around this slot with an upwardly open annular groove holding an O-ring that projects above an upper face of this bottom wall. A nozzle sheet lies atop this O-ring, which actually is not circular but which instead is oblong and at least 1 m long has two long straight and parallel side regions bridged at the ends by semicircular regions, and is held thereagainst by the high pressure in the housing chamber. The liquid passes through small holes in the needle sheet to form the treatment jets.
In view of the pressures being used, the needle sheet and O-ring of such a device are subjected to considerable wear and need to be replaced periodically. In the oldest machines the entire housing was dismantled to do this, but more modern systems such as in above cited U.S. Pat. No. '654 have a setup for installing such an oblong seal or an O-ring in a holder or seal-ring groove in a nozzle beam or a housing for the nozzle beam.
To this end the nozzle beam is typically formed with closable access slots that open into the chamber immediately above the upper face of the bottom wall formed with the groove holding the O-ring at each end of the beam. When the O-ring (and frequently also the nozzle sheet) need to be replaced, the chamber is drained and ports at the end of this slot are opened. Then the worn parts are removed. A fresh O-ring is fitted to a tool that stretches it, thereby reducing its cross-sectional diameter, and this tool is threaded through the nozzle beam to align the stretched O-ring above the groove it is to fit to. Then the O-ring is pried at each end off the tool and, if all goes well, it snaps into place in the groove. The old or a fresh nozzle sheet is put back in position, the ports are closed, and the apparatus can be refilled and reused.
This servicing operation, which is a regular occurrence, therefore requires two people to perform, one at each end of the beam. One fits the tool carrying the stretched seal through the beam, then both of the service personnel work the seal off the tool and fit it into the groove. The job cannot be done readily by one person.